Production of artificial materials and apparatus therefor



June 29, 1937. E. KINSELLA 2,085,532

PRODUCTION OF ARTIFICIAL MATERIALS AND APPARATUS THEREFOR Filed Jan. 11,1935 2 Sheets-Sheet l EDWARD KIN SELLA mvsnrroa ATTORNEYS June 29, 1937.I E. KINSELLA v w 2,085,532

PRODUCTION OF ARTIFICIAL MATERIALS AND APPARATUS THEREFOR Filed Jan. 11,1955 2 Sheets-Sheet 2 Flt-3-2- I 35 I L J EDWARD KlN lg gl f PatentedJune 29, 1937 PATENT OFFICE PRODUCTION OF ARTIFICIAL MATERIALS ANDAPPARATUS THEREFOR Edward Kinsella, Spondon, near Derby, England,

assignor to Celanese Corporation of America, a corporation of DelawareApplication January 11, 1933 Serial No. 651,159 In Great Britain January30, 1932 2 Claims.

This invention relates to the manufacture of artificial materials, andin particular to the manufacture of artificial films or foils,especially of thin foils suitable for use as Wrapping paper, elec tricalinsulation or other purposes. i

The manufacture of such foils is effected by depositing a thin layer ofa solution of the base material of the foil in any suitable solventliquid on to a smooth surface, causing the thin layer to set andthereafter stripping the foil from the The smooth surface on to whichthe layer of solution is deposited is generally either in the form of awheel or drum or an endless metal, paper, or other band, the drum orband moving continuously through the setting medium so that productionof the foil forms a continuous operation. The layer is deposited on themoving surface at any point in its path, and is carried thereby. throughthe setting medium to the point at which stripping takes place,generally near to the depositing point so as to use to the full thelength or periphery of the surface as asetting run.

It will be readily understood that apart from the manner in which thelayer is deposited on the smooth surface, the quality of the product,and in particular its appearance, depends to a very large extent uponthe nature of the surface itself. For instance, it is generallydesirable, particularly where the foil is intended for use as a Wrappingmaterial, in which case transparency is usually regarded as important,to produce a material whose surface is as smooth and even as possible soas to impart a fine glossyappearanoe to the product, Since, however, oneface of the foil is formed in intimate contact with the surface on whichthe solution has been deposited, this surface partakes exactly of theconfiguration of the surface, so that anyirregularities found thereonare exactly reproduced. In the case of transparent foil in particularany such irregularities detract appreciably from the value of the foil.In addition, variations in the evenness of the surface may affect tosome extent the thickness ofthe product which, apart from causingdiminution in the strength of the material and its permeability tomoisture and requiring a greater weight of material than is necessaryfor the desired strength, etc., may also reduce its good appearance onaccount of the tendency to produce Waves or cockles in the material.

A very convenientform of apparatus consists in an endless band having asuitably smooth glossy surface, since such band can easily be formed ofany desirable length in accordance with the length of drying runrequired (this being a function of the nature of the material formingthe film, the concentration and Viscosity etc. of the solution, and therate at which production is to take place), Without increasing thecomplication and weight of the apparatus. The band thus enables thedesign of the apparatus to be flexible in character, long bands merelyrequiring simple addition to the length of the drying run.

The present invention is directed particularly to the use of this typeof apparatus, and has for its object to provide a band which willproduce the highest quality of film or foil and be serviceable inoperation.

According to the invention, a metal band is used, the band itself havingan exceedingly highly polished surface, so that the solution can bedeposited directly upon the band. In order to ensure that the highpolish of the surface is maintained, the metal of the band is such thatit is capable of withstanding any corrosive influence fora considerabletime; that is to say the band should be substantially unaffected by thespinning solution itself or atmospheric conditions in the case of thedry method of operation, and by the setting bath in the case of the wetmethod of operation. Further, (and this is of the greatest importance)the band must also be capable of being flexed repeatedly withoutdeterioration in its passage from the apparatus in the cycle ofoperations involving deposition of the solution, drying of the film orfoil, and stripping. Further, apart from being capable of receivingexceedingly high polish, the surface of the band should be sufficientlytough to resist wear to a very marked extent.

Accordingly, therefore, the metal of which the band is composed is ofhigh elasticity, so that after being flexed, even after a very largenumber of times, it returns to its original form. In other Words thehand does not absorb any internal work performed on it bythe act offlexing, or become stretched or strained, so that it maintains itssmoothness of surface.

For this purpose stainless steel is particularly suitable not only byits intrinsic anti-corrosive face of bands made from this material ispractically unaffected by any corrosive influences encountered in themanufacture of films or foils, so that its smoothness remains unimpairedfor long periods, thus allowing the apparatus to continue in operationwithout the necessity for fairly frequent stoppages for renewal of thesurfaces. Further, the particularly smooth finish which can be impartedto the stainless steel or nickel surface enables very highly glossedfoils to be produced by deposition of solution directly on to thesurfaces and avoids the necessity for applying coatings of gelatin orlikematerial to receive the solution.

. Repeated stripping of film or foil over long periods tends to exert awearing or abrading action on the depositing surface. In the caseofstainless steel its toughness resists such action to a very high degree,so-that even particularly highly polished surfaces are very littleaffected if at all, while the relatively softer nickel is also veryserviceable in this respect because of the toughness which can beimparted in rolling nickel into 'a thin band.

A. further advantage resides in the fact that even if the surfacedeteriorates to any small extent for any reason after being in use forsome may take place can only do so to an extremely small depth, it ispossible to usethe stainless steel or nickel as a comparatively thinband which is yet capable of being re-polished repeatedly, and so has avery considerable life. a

As has already been indicated, the quality of the films or foilsproduced depends to a very large degree upon the smoothness of thedepositing surface, and it is here emphasized that exceedingly.greatcare must be observed in finishing the bands to ensure that despiteapparent high polish no minute scratches of any description can be foundin the surface. In fact, the surface should be given a mirror polish andvery great care should be taken in operating the band to ensure,

that no damage'is' done to the surface. When necessary, especially ifthe band has been in operation for some time, re-polishing may beresorted to. I 7

Any joint in theband must be very carefully finished, not only to ensurethat the surface smoothness of the band is unbroken but that the bandremains resistant to corrosion at the joint. If in the formation of thejoint heat treatment, e. g. welding, is used which may have affected thetoughness or resistance 'of the metal,'suitable treatment such' as coldrolling should be applied to the joint before its final smoothing andpolishing.

' The following indicatesthe general steps to be followed in theproduction of a nickel band for the purpose of the invention. A band ofsuitable length, width, and thickness isthoroughly' an nealed,"and itsends are perfectly cleaned in readiness for jointing. This is effectedby properties and capability for'receiving and mainhammer-we1ding in areducing atmosphere at a relatively low temperature (say 200 0. belowthe melting point). It is preferred that the joint be made in this: way,since it avoids the danger of warping which is present if highertemperatures are employed for the purpose, and the difficulty ofsubsequently eliminating the warping.

The welded band is then subjected to a coldrolling process which bringsit to the desired final thickness, this operation being carried outcarefully to leave the band as straight as possible. At the same time,the working makes the metal at the joint substantially identical instructure to that in the rest of the band, and imparts a high degree ofelasticity to the band, as well as hardening it and giving it a toughcharacter.

Slight stretching may then be resorted to in order to make the band runtrue and straight, this being conveniently effected on a pair of drumswhich can be forced apart while rotating to subject the whole band tothe stretching tension. Nickel bands produced in this way have not onlya high degree of hardness (Brinell figure 114 or so) but also veryconsiderable tensile strength (approximately 130,000 lbs.) and whenfinally polished are particularly suited as film or foil-formingsurfaces.

The use of bands as above described enables machines of differentcapacities to be readily constructed, since it is quite a simple matterto .obtain difierent lengths of drying run in accordance with thethickness or character of the foil or the speed of the machine withoutserious modification of the machine apart from the length.

Apparatus embodying the invention is illustrated in the accompanyingdrawings in which Fig. 1 shows in side elevation a band machine having apair of supporting drums giving the band two parallel setting runs;

Fig. 2 is a part sectional view showing details of the tensioning gearand its relation to one drum and the drum casing;

Fig. 3 is a section taken on the line 3-3 of Fig. 2; and

Fig. 4 is a part-sectional plan view of the movable drum machine withtension adjusting gear similar to that shown in Figs. 1 to 3, togetherwith pressure means for automatic tension adjustment.

Fig. 1 shows a band 5 carried by drums 6, '1 within a casing 8. The band5 may be, for example, .03 inch in thickness, and so of sufiicientflexibility to pass round drums of quite small diameter; it isadvisable, however, in order to retion of cellulose acetate in acetoneis deposited on the band near the point where it reaches the top of thedrum 6 by means of a box 9 supplied, for example, by means of a pump infrom any suitable container H. Pressure feed means such as the pump I 0'are particularly desired with high concentration solutions, e. g. 33%acetone solutions; because of .the high viscosity of such solutions.

The casing 8 is arranged to enclose the upper run l2 of ,the' band, thissection of the casing being heated by means of heater elements l3 underseparate control, e. g. by means of cocks l4 so as to regulate thetemperature conditions along this run. The atmosphere within the casingon the upper run may be maintained substantially saturated with acetonewhich is withdrawn through an outlet l5 for recovery.

The lower run l6 of the band is also enclosed by the casing 8, and .airis admitted at I! tocomplete the drying of the foil on the band, thisair, together with evaporated solvent, being withdrawn by the outlet l8. The foil is stripped from the band at the roll 6 and wound in amanner to be described later. The lengths of the drying runs depend onthe conditions under which the machine is to work, such as band speed,and thickness of foil to be produced.

In order to tension the band, and especially to put it under eventension over its whole width, the gearing shown in detail in Figs. 2 and3 is employed. The drum 1 is mounted in bearing blocks l9 longitudinallymovable in slides H9 on the machine frame. The blocks l9 are connected(as shown in Fig. 1) to long screwed rods 20 on which are screwed nuts2!. On each nut 2| is slidably keyed a hand wheel 22 which enables eachbearing block l9 to be given a coarseadjustment in the hand wheel of theother block, or, by means of bevel gears'23 keyed to the nuts 2| andconnected together by bevel gears 24 on the cross shaft 25, for both ofthe bearing blocks to be given a coarse-adjustment by operation ofeither of the hand wheels 22. When independent adjustment is required,one of the gears 24 may be slid out of engagement with its bevel 23being slidably keyed to the shaft 24 for this purpose, as shown in Fig.2.

Freely mounted on each nut 2| is a worm wheel 26 fitted with dog teeth21 adapted to engage corresponding teeth 23 on the hand wheel 22. Thehand wheel 22 is normally urged'by a spring 29 to bring about engagementbetween the teeth 21, 28 so as to clutch the worm wheel 26 to the handwheel 22. A pivoted latch 30, however, enables the worm wheel 26 and thehand wheel 22 to be kept out of engagement with each other.

For convenience in assembly, the nut 2| has keyed to it a sleeve I2l towhich the hand wheel 22 and the bevel gear 23 are keyed and on which theworm wheel 26 is free to rotate.

The worm wheels 26 engage worms 3|, 32, the worm 32 being secured to across shaft 33 while the worm 3| is carried by a sleeve 34 freelymounted on the shaft 33. At one end of the shaft 33 is secured a toothedmember 35 adjacent. to which is a second toothed member 36 secured tothe sleeve 34.

A housing 3'! carried by a hand wheel 38 on the end of the shaft 33 istoothed internally at 39 to mesh with the toothed members 35, 36. Thehousing 31 is slidable with respect to the shaft 33 so as to bring theteeth 39 into engagement with both of the toothed members 35, 36 or witheither of these as desired, a plunger 49 enabling the housing to beretained in any selected position. With both members 35, 36 engaged,rotation of the hand wheel 38 causes the worms 3|, 32 to rotate both ofthe worm wheels 26, so that if both of these wheels are clutched to thehand wheels 22 on the screwed rods 20, both bearing blocks l9 are movedto an equal extent, the worm gearing enabling a fine adjustment to beeffected in the position of the blocks. With only one of the members 35,36 in engagement, the corresponding worm 3| or 32 is rotated by the handwheel 38 so that fine adjustment is effected in the correspondingbearing block IS. The adjusting gear is carried by brackets 4| from thecasing 8.

In Fig. 4 is shown a similar adjusting gear with, however, theconnecting bevels 24, 26 omitted, coarse-adjustment of the blocks l9being effected by independent operation of the hand wheels 22. Ifdesired, however, provision may be made for simultaneous adjustment asshown in Figs. 2 and 3. The adjusting gear in Fig. 4 is carried by aframe 42 slidably mounted on rods 43 connected to the frame of an aircylinder 44. The frame 42 is connected to a ram 45 workingin the aircylinder.

Coarse-adjustment of the band tension can be effected by the hand wheels22 and fine adjustment by means of the hand wheel 38, this adjustmenttaking place relative to the frame 42. During operation of the machine,the band is maintained tensioned by means of the cylinder 44, and sinceboth bearing blocks I9 are aifected equally by the frame 42, eventension is maintained across the width of the band.

The foil is stripped by means of the roller 46 slightly spaced from thedrum 6 and is wound on to a spool 41' contacting with the roller 46. Inorder to wind the foil smoothly, the spool 41 is driven by frictionwheels 48, 49 which tend to over-drive the spool. On completion of thespool 41, a second spool 50 is swung into position against the roller46, the spools being carried on an arm 5|, pivoted in the lower end of aswinging frame 52 carried by a. shaft 53 bearing a sprocket 54 by whichthe friction gear is driven. For further details of this take-up device,reference should be had to U. S. application S. No. 499,950, filed 4thDecember, 1930.

What I claim and desire to secure by Letters Patent is:-

1. Apparatus for the manufacture of films and foils, said apparatuscomprising an endless flexible band of nickel, cold-worked afterjointing so as to be substantially uniform over its whole length.

2. Apparatus for the manufacture of films and foils, said apparatuscomprising an endless flexible band of nickel, jointed byhammer-welding, and cold-worked after jointing so as to be substantiallyuniform over its whole length.

EDWARD KINSELLA.

